We describe designing and generating massive terrain data sets using VRML 97. Our design aims for efficient navigation of geo-referenced terrain data sets using a standard VRML browser. This involves issues such as navigating models with many millions of polygons, managing deep level-of-detail (LOD) hierarchies, dealing with data precision problems to model the earth at submeter resolution, translating between geographic coordinate systems, and dynamically selecting different sets of geo-referenced data. We present solutions to all of these problems using currently available technologies. We also present a custom terrain visualization package called TerraVision II engineered to efficiently and seamlessly browse the VRML constructs that we create. This specialized browser, along with various software tools that implement our work, is freely available to the VRML community to encourage and facilitate further work in this area.